// Copyright 2015 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package s2

import (
	"math"
	"testing"

	"github.com/golang/geo/r3"
)

func TestCol(t *testing.T) {
	tests := []struct {
		have *matrix3x3
		col  int
		want Point
	}{
		{&matrix3x3{}, 0, OriginPoint()},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			0,
			Point{r3.Vector{1, 4, 7}},
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			2,
			Point{r3.Vector{3, 6, 9}},
		},
	}

	for _, test := range tests {
		if got := test.have.col(test.col); !got.ApproxEqual(test.want) {
			t.Errorf("%v.col(%d) = %v, want %v", test.have, test.col, got, test.want)
		}
	}
}

func TestRow(t *testing.T) {
	tests := []struct {
		have *matrix3x3
		row  int
		want Point
	}{
		{&matrix3x3{}, 0, OriginPoint()},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			0,
			Point{r3.Vector{1, 2, 3}},
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			2,
			Point{r3.Vector{7, 8, 9}},
		},
	}

	for _, test := range tests {
		if got := test.have.row(test.row); !got.ApproxEqual(test.want) {
			t.Errorf("%v.row(%d) = %v, want %v", test.have, test.row, got, test.want)
		}
	}
}

func TestSetCol(t *testing.T) {
	tests := []struct {
		have  *matrix3x3
		col   int
		point Point
		want  *matrix3x3
	}{
		{
			&matrix3x3{},
			0,
			Point{r3.Vector{1, 1, 0}},
			&matrix3x3{
				{1, 0, 0},
				{1, 0, 0},
				{0, 0, 0},
			},
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			2,
			Point{r3.Vector{1, 1, 0}},
			&matrix3x3{
				{1, 2, 1},
				{4, 5, 1},
				{7, 8, 0},
			},
		},
	}

	for _, test := range tests {
		if got := test.have.setCol(test.col, test.point); !matricesApproxEqual(got, test.want) {
			t.Errorf("%v.setCol(%d, %v) = %v, want %v", test.have, test.col, test.point, got, test.want)
		}
	}
}

func TestSetRow(t *testing.T) {
	tests := []struct {
		have  *matrix3x3
		row   int
		point Point
		want  *matrix3x3
	}{
		{
			&matrix3x3{},
			0,
			Point{r3.Vector{1, 1, 0}},
			&matrix3x3{
				{1, 1, 0},
				{0, 0, 0},
				{0, 0, 0},
			},
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			2,
			Point{r3.Vector{1, 1, 0}},
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{1, 1, 0},
			},
		},
	}
	for _, test := range tests {
		if got := test.have.setRow(test.row, test.point); !matricesApproxEqual(got, test.want) {
			t.Errorf("%v.setRow(%d, %v) = %v, want %v", test.have, test.row, test.point, got, test.want)
		}
	}
}

func TestScale(t *testing.T) {
	tests := []struct {
		have  *matrix3x3
		scale float64
		want  *matrix3x3
	}{
		{
			&matrix3x3{},
			0,
			&matrix3x3{},
		},
		{
			&matrix3x3{
				{1, 1, 1},
				{1, 1, 1},
				{1, 1, 1},
			},
			0,
			&matrix3x3{},
		},
		{
			&matrix3x3{
				{1, 1, 1},
				{1, 1, 1},
				{1, 1, 1},
			},
			1,
			&matrix3x3{
				{1, 1, 1},
				{1, 1, 1},
				{1, 1, 1},
			},
		},
		{
			&matrix3x3{
				{1, 1, 1},
				{1, 1, 1},
				{1, 1, 1},
			},
			5,
			&matrix3x3{
				{5, 5, 5},
				{5, 5, 5},
				{5, 5, 5},
			},
		},
		{
			&matrix3x3{
				{-2, 2, -3},
				{-1, 1, 3},
				{2, 0, -1},
			},
			2.75,
			&matrix3x3{
				{-5.5, 5.5, -8.25},
				{-2.75, 2.75, 8.25},
				{5.5, 0, -2.75},
			},
		},
	}

	for _, test := range tests {
		if got := test.have.scale(test.scale); !matricesApproxEqual(got, test.want) {
			t.Errorf("%v.scale(%f) = %v, want %v", test.have, test.scale, got, test.want)
		}
	}
}

func TestMul(t *testing.T) {
	tests := []struct {
		have  *matrix3x3
		point Point
		want  Point
	}{
		{&matrix3x3{}, Point{}, Point{}},
		{
			&matrix3x3{
				{1, 1, 1},
				{1, 1, 1},
				{1, 1, 1},
			},
			Point{},
			Point{},
		},
		{
			// Identity times something gives back the something
			&matrix3x3{
				{1, 0, 0},
				{0, 1, 0},
				{0, 0, 1},
			},
			Point{},
			Point{},
		},
		{
			// Identity times something gives back the something
			&matrix3x3{
				{1, 0, 0},
				{0, 1, 0},
				{0, 0, 1},
			},
			Point{r3.Vector{1, 2, 3}},
			Point{r3.Vector{1, 2, 3}},
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			Point{r3.Vector{1, 1, 1}},
			Point{r3.Vector{6, 15, 24}},
		},
	}
	for _, test := range tests {
		if got := test.have.mul(test.point); !got.ApproxEqual(test.want) {
			t.Errorf("%v.mul(%v) = %v, want %v", test.have, test.point, got, test.want)
		}
	}
}

func TestDet(t *testing.T) {
	tests := []struct {
		have *matrix3x3
		want float64
	}{
		{
			&matrix3x3{},
			0,
		},
		{
			// Matrix of all the same values has det of 0.
			&matrix3x3{
				{1, 1, 1},
				{1, 1, 1},
				{1, 1, 1},
			},
			0,
		},
		{
			// Identity matrix has det of 1.
			&matrix3x3{
				{1, 0, 0},
				{0, 1, 0},
				{0, 0, 1},
			},
			1,
		},
		{
			&matrix3x3{
				{-2, 2, -3},
				{-1, 1, 3},
				{2, 0, -1},
			},
			18,
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			0,
		},
		{
			&matrix3x3{
				{9, 8, 7},
				{6, 5, 4},
				{3, 2, 1},
			},
			0,
		},
		{
			&matrix3x3{
				{1.74, math.E, 42},
				{math.Pi, math.Sqrt2, math.Ln10},
				{3, math.SqrtPhi, 9.8976},
			},
			-56.838525224123096,
		},
	}

	for _, test := range tests {
		if got := test.have.det(); !float64Eq(got, test.want) {
			t.Errorf("%v.det() = %v, want %v", test.have, got, test.want)
		}
	}
}

func TestTranspose(t *testing.T) {
	tests := []struct {
		have *matrix3x3
		want *matrix3x3
	}{
		{&matrix3x3{}, &matrix3x3{}},
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			&matrix3x3{
				{1, 4, 7},
				{2, 5, 8},
				{3, 6, 9},
			},
		},
		{
			&matrix3x3{
				{1, 0, 0},
				{0, 2, 0},
				{0, 0, 3},
			},
			&matrix3x3{
				{1, 0, 0},
				{0, 2, 0},
				{0, 0, 3},
			},
		},
		{
			&matrix3x3{
				{1, 2, 3},
				{0, 4, 5},
				{0, 0, 6},
			},
			&matrix3x3{
				{1, 0, 0},
				{2, 4, 0},
				{3, 5, 6},
			},
		},
		{
			&matrix3x3{
				{1, 1, 1},
				{0, 0, 0},
				{0, 0, 0},
			},
			&matrix3x3{
				{1, 0, 0},
				{1, 0, 0},
				{1, 0, 0},
			},
		},
	}

	for _, test := range tests {
		if got := test.have.transpose().transpose(); !matricesApproxEqual(got, test.have) {
			t.Errorf("%v.transpose().transpose() = %v, want %v", test.have, got, test.have)
		}

		if got := test.have.transpose(); !matricesApproxEqual(got, test.want) {
			t.Errorf("%v.transpose() = %v, want %v", test.have, got, test.want)
		}

	}
}

func TestString(t *testing.T) {
	tests := []struct {
		have *matrix3x3
		want string
	}{
		{
			&matrix3x3{
				{1, 2, 3},
				{4, 5, 6},
				{7, 8, 9},
			},
			`[ 1.0000 2.0000 3.0000 ] [ 4.0000 5.0000 6.0000 ] [ 7.0000 8.0000 9.0000 ]`,
		},
		{
			&matrix3x3{
				{1, 4, 7},
				{2, 5, 8},
				{3, 6, 9},
			},
			`[ 1.0000 4.0000 7.0000 ] [ 2.0000 5.0000 8.0000 ] [ 3.0000 6.0000 9.0000 ]`,
		},
	}

	for _, test := range tests {
		if got := test.have.String(); got != test.want {
			t.Errorf("%v.String() = %v, want %v", test.have, got, test.want)
		}
	}
}

func TestFrames(t *testing.T) {
	z := PointFromCoords(0.2, 0.5, -3.3)
	m := getFrame(z)

	if !m.col(0).IsUnit() {
		t.Errorf("col(0) of frame not unit length")
	}
	if !m.col(1).IsUnit() {
		t.Errorf("col(1) of frame not unit length")
	}
	if !float64Eq(m.det(), 1) {
		t.Errorf("determinant of frame = %v, want %v", m.det(), 1)
	}

	tests := []struct {
		a Point
		b Point
	}{
		{m.col(2), z},

		{toFrame(m, m.col(0)), Point{r3.Vector{1, 0, 0}}},
		{toFrame(m, m.col(1)), Point{r3.Vector{0, 1, 0}}},
		{toFrame(m, m.col(2)), Point{r3.Vector{0, 0, 1}}},

		{fromFrame(m, Point{r3.Vector{1, 0, 0}}), m.col(0)},
		{fromFrame(m, Point{r3.Vector{0, 1, 0}}), m.col(1)},
		{fromFrame(m, Point{r3.Vector{0, 0, 1}}), m.col(2)},
	}

	for _, test := range tests {
		if !pointsApproxEqual(test.a, test.b, epsilon) {
			t.Errorf("%v != %v", test.a, test.b)
		}
	}
}